Static annunciator with acknowledgment and ring back



Nov. 22, 1966 M. KRAUs 3,287,717

` STATIC ANNUNCIATOR WITH ACKNOWLEDGMENT AND RING BACK Filed July 30, 1962 5 Sheets-Sheet 2 FLASHER V BY /vwvr// TEST B+ [AUDIBLEI FLAsHERl E z Nov. 22, 19

M. KRAUS STATIC ANNUNCIATOR WITH ACKNOWLEDGMENT AND RING BACK Filed July 30, 1962 5 Sheets-Sheet 5 NORMAL RETURN NORMAL ALERT BEFORE ACK. TO RESET TEST ACK. NORMAL LAMP OFF FLASH FLASH BRIGHT BRIGHT OFF FLASH AUDIBLE OFF ON ON OFF OFF OFF ON/OFF N.O. CONTACT OPE N CLOSED OPEN CLOSED OPEN OPEN OPEN' N.C. CONTACT CLOSED OPEN CLOSED OPEN CLosEO CLOSED cLosEo FIG?. f2

I l l L A A l Il lqrfd |44r2l l vl 1 r 1L Il l /464 n EAZA/VF /0 sw c a /2 fm fea/f6. 2 fr 4 5+ ACK. 5557' /9 2i .wa/Md Fui/md FIGTO. f6 f5' NORMAL RETURN NORMAL ALERT BEFORE ACK. TO RESET TEST ACK. NORMAL LAMP OFF FLASH FLASH BRIGHT FLASH OFF FLASH OFF ON ON OFF OFF OFF ON /OFF AUD'BLE 2 OFF OFP oN OFF oN oFF OFF/ON N.o. CONTACT OPEN CLOsEo OPEN CLOsEO OPEN OPEN OPEN N OCoN-rACT C'LosEO OPEN cLosEn OPEN CLOSED CLOSED CLosED ...lm m V l 25 A A A 5 l 4,475/ 447:2 y l //5 n 1 IVI L 1 AM L .zj Fmi/fee /w 7| f4' f-c v .1 -'x7' AWF 20 /24 /70 /75 /755- /g 23 INVENTOR: rffr 196A- EffT MURRAY KRAUS ATTTIS NOV. 22, 1966 M, KRAUS 3,287,717

STATIG ANNUNCIATOR WITH ACKNOWLEDGMENT AND RING BACK Filed July 30, 1962 5 Sheets-Sheet '4 F IG. I4.

#V0/BLE FL HSHER RETURN NORMAL ALERT ACK, TO RESET TEST NORMAL l ALARM OFF RED RED RED OFF RED LAMP FLASH BRIGHT BRIGHT FLASH SUBSEQ- OFF WHITE WHITE OFF OFF WHITE LAMP FLASH BRIGHT BRIGHT AUDIBLE OFF ON OFF OFF OFF OFF/ON FIQI am/aw' auf ATTYS.

M. KRAUS Nov. 22, 1966 STATIC ANNUNCIATOR WITH ACKNOWLEDGMENT AND RING BACK Filed July so, 1962 5 Sheets-Sheet 5 |NvEN1-on MURRAY KRAUS ATT YS.

United States Patent vania Filed July 30, 1962, Ser. No. 213,277 13 Claims. (Cl. 340-213) This invention relates to an annunciator system and individual points therein each of which is responsive to the condition of a sensing means in the form of switch contacts at the monitored point or location and each of which has at least one lamp to indicate the normal condition of the contacts in one state of the lamp and an alert condition of the contacts in the other state of the lamp. More specifically, the invention relates to the system and circuitry of an annunciator point of extreme simplicity lending itself to small module, transistorized construction and at the same time extremely low cost. This annunciator point is capable of a multitude of variations to accomplish different results and effects and is capable of using either normally open and normally closed contacts as the sensing means.

Annunciators have been used for years to indicate quickly the location of trouble at one or more remote locations by observation at a central monitoring point, usually a panel board with lamps identifying various locations monitored. The remote points or locations are trouble sensitive regions of the devices monitored which are provided with sensing means usually a transducer including a switch with either normally closed or normally open contacts which change state in response to the changes in the such sensed conditions as pressure, temerature, mechanical movement, etc.

Use of annunicators has been limited for the most part to installations employing expensive capital equipment, such as power plants or chemical processing plants where the extremely heavy investment in machinery and equipment has justified a substantial expenditure for annunciator equipment. Furthermore, annunciator equipment has been relatively large and bulky particularly in the complex relay circuits and equipment which have been employed. Some attempts have been made to reduce the size and bulk of the equipment, but commercial systems by and large remain bulky, complex, expensive and dil'licult to install and maintain.

The present invention relates to an annunciator system which has been developed to use transistors and other semi-conductor devices and other small components and which adapts itself to use of printed circuit boards of small size, i.e., a board with its components having a thickness usually less than an inch and other dimensions on the order of several inches. Moreover, the present invention lends itself to a modular construction whereby one such printed circuit board supplies all the switching and control electronics required for one, two, three or four points of an annunciator system. Similar printed circuit modules may be provided for circuitry for other system functions such as the flasher, the power supply (B+), and audible control circuits. Simple plug in connections connect the modules and in some cases instead of being placed on their individual cards, several modules may be combined on one card. It should be understood that many annunciator point modules can employ the Vsame flasher, the same power supply, the same audible, and other circuits. Each point will, of course, require its own indicator light or lights and sensing means, but all points in a group may share cornmon acknowledgement, reset, and test switches which are preferably manually actuated push buttons.

The annunciator point modules of the present invention have the great advantage of versatility in type of performance to rbe yattained as well as conditions under which a specific type of performance is to be obtained. The circuitry employed is stable over wide ranges of temperature despite the known ltemperature sensitivity of transistors. The voltages employed with a given module may vary through wide ranges of D.C. and over a fairly substantial range of 60 cycle A.C. Not only are the printed circuit modules small and convenient to handle cards but they are inexpensive to manufacture so that they may be discarded if they become defective in use and a new card easily substituted particularly where employed with plug-in type circuitry. Use with plug-in circuitry is facilitated by .arrangement of their terminals in standard locations along the edge of a card. Standard locations may even lbe used with various types of points so that the user has a choice of sequence of operation in a given location. Moreover, la standard annunciator point module according to the present invention provides the` option of normally open or normally closed contacts by a simple cir-cuit change involving use of a jumper connection.

The various point modules for achieving different sequences are derived from a basic point module which employs a gate responsive to sensing contacts to permit a lamp to change its condition. This gate is controlled by a flasher which causes the lamp to flash upon receiving a signal from the sensing means. Acknowledgment means, including a flip-flop and a manually controlled switch, is so arranged that actuation -of the switch changes the state of the flip-fiop which is connected to the gate in such a way as to overcome the effect of the flasher and cause a steady acknowledged alert condition of the lamp following acknowledgment.

Upon this simple basic circuit are built lmany variations of annunciator combinations including those involving one lamp or more than one lamp. For example, some points retain an alert signal after normal condition of the monitoring device has allowed the sensing means to return to normal while others do not. Means for resetting the device is necessitated by retention of an alert signal even after the sensing switch returns to normal. Two or more lamps in combination in a single point employing :a group of interdependent annunciator points enable, for example, a system in which the first point to become abnormal lights one kind of lamp whereas the next lights another kind.

For a lbetter understanding of the present invention, reference is made to the accompanying drawings, in which:

FIG. 1 is a block diagram showing alternative sensing means connections in the basic circuit of the annunciator point of the present invention;

FIG. 2 is a chart of the sequence of operation of the circuit of FIG. 1;

FIG. 3 is a circuit diagram of a preferred form of the circuit of FIG. 1;

FIG. 4 is a block diagram of a modified type annunciator circuit;

FIG. 5 is a sequence chart applying to the circuit of FIG. 4;

FIG. 6 is a circuit diagram showing :a preferred form of the circuit of FIG. 4;

FIG. 7 is a block diagram of still another annunciator point modification;

FIG. 8 is a sequence chart for the annunciator point of FIG. 7;

FIG. 9 is a block diagram of still another annunciator point modification;

FIG. 10 is a sequence chart for the annunciator point of FIG. 9;

FIG. 11 is a block diagram of a still further modified annunciator point circuit;

FIG. l2 is a sequence chart for the annunciator point of FIG. 1l;

FIG. 13 is a circuit diagram of a preferred embodiment of the circuit of FIG. 1l; and

FIG. 14 is a representative block diagram showing various possible connections for an annunciator system group employing multiple annunciator point modules.

Referring first to FIG. 1, there is shown the annunciator point module of the basic tube in accordance with the present invention. The annunciator point module itself is that part of the circuitry within the dashed line and this circuitry including the various circuit elements are included as an integral module on the printed circuit board. The annunciator module includes an input gate 11A or 11B, which in some cases is omitted or cornbined with a flip-flop or other circuitry. The sensing means 12A or 12B are external of the circuit board and connected to the gates 11A and 11B, respectively. As indicated by the dashed lines in connection with sensing means 12B, only one of the sensing means is employed and the other is omitted. Sensing means 12A is a switch in the region to be monitored consisting of normally open contacts which are closed on occurence of the alert condition to be monitored. Alternatively, normally closed contacts 12B, which are opened by occurrence of the alert condition, may be employed. In preferred ernbodiments instead of employing separate gates 11A or 11B, a minor circuit modification permits the use of the same active element as the gate in either case. The signal from g-ate 11A or gate 11B, whichever is used in a particular case, is fed to the signal terminal of gate 13, whose output is connected to lamp indicator 14, here shown as two lights of the same type in parallel. Additionally an extension light 14a at some location remote from the annunciator panel board may be employed. It is frequently desirable to employ an amplifier 15 between the lamp or lamps 14 and gate 13. Connected to the control terminal of gate 13 is flasher unit 16 which provides a signal which causes the gate 13 to alternately open and close, thereby causing the lamps 14 to flash on and off alternately. The input signal from gate 11A or gate 11B also causes flip-flop 17 to assume one of its stable states and causes the audible circuitry 18 to be energized to produce an audible sound from a horn, buzzer or other audible device. When an observer on the premises sees `a ashing light of lamp 14 or hears the audible sound, by pushing the acknowledgment button to cl-ose the acknowledgment switch 19 he produces a pulse which causes flip-flop 17 to change its state and provide a continuous signal to the control terminal of gate 13. The steady signal overcomes the flasher and causes the gate to assume a state which is ordinarily conductive. This also causes the lamps 14 to assume their acknowledged alert condition which ordinarily is lit to give a steady bright light.

The sequence of operation just described is tabulated in the chart of'FIG. 2. It will be observed that this sequence requires no reset because in the event that the sensing means returns to normal either before or following acknowledgment the lamp will return to its normal condition, which in the ordinary system is off.

A test switch 20 is provided to test the operability of the circuit and to make sure lights are not burned out. When the test switch is closed, the same conditions obtain as when sensing means switch contacts 12A or 12B are energized so that the lamp 14 is flashed.

A preferred circuit for the module shown in FIG. l and having the sequence of FIG. 2 is shown in FIG. 3. Referring to FIG. 3, the same gate 11 serves whether for normally open or closed contacts so that separate gates 11A and 11B as shown as possibilities in FIG. l are not necessary. If normally open contacts 12A are employed, when they are closed, they complete a circuit from B+ 4 to ground through resistors R1', R2 and R3 which pulls the base of PNP transistor Q1 negative from the B+, which it assumed through its connection to resistor R3', thereby rendering it conductive. On the other hand, if normally closed contacts 12B are employed, B+ is connected through these contacts to the junction of resistors R1 and R2 so that the base of transistor Q1 is maintained positive. In this situation the contact for the terminal for the normally open contact is jumpered to ground (as shown in dashed lines) so that the full voltage drop of B+ to ground appears across resistor R1. Then when normally closed contacts 12B open, the same potential distribution appears as in the situation of the opening of the normally open contact, the base of transistor Q1 is pulled negative and causes the transistor to conduct. It will be appreciated that use of contacts 12A and 12B at the same time is inconsistent so that the choice of one is made, the other is eliminated and thel circuit adjusted accordingly before use. When transistor Q1 is rendered conductive by actuation of the sensing means it effectively applies a signal to the emitter terminal of transistor Q2 which serves as gate 13 leaving it to act as the switch or relay for energizing the lamps 14. The base of transistor Q2 which serves as the control electrode for'the gate 13 is connected through coupling resistor R4 and diode D1 to the flasher 16. T he flasher supplies alternating positive and negative pulses to the base of transistor Q2, thereby periodically rendering that NPN transistor conductive when pulsed positive. The conduction path from B+ to ground includes resistors R5 and R6, transistors Q2 and Q1 and resistors R7 and R8. This conduction lowers the potential on base of PNP transistor Q3 which acts as an amplifier of any signal through transistor Q2 and therefore causes lamps 14 to flash alternately on and off. Since the lamps are in a circuit, the current can then ow from B+ through diode D2, transistor Q3, resistor R10 and the lamps to ground. Zener diode DZ3 and diode D2 are preferably outside the printed circuit board and may serve in common for all points in the same group with this one. These diodes function as voltage-dropping devices to provide voltage somewhat lower than B+ in two stages. Y

It will also be observed that the emitter of transistor Q1 is connected through ycapacitor C1, diode D4 and resistor R12 to the audible module 18 so that, upon rendering gate 11 conductive by actuation of switch 12A or 12B, as the case may be, a negative pulse is produced which passes through the circuit elements described to -trigger a flip-flop or like device in the audible module circuit.

When the acknowledgement push button is closed, separate contacts not shown but associated with switch 19 as another pole interrupt the audible. In addition, a negative pulse occurs through resistor R13 and diode D5 to the base of transistor Q4 which has previously been biased positively through resistor R14 to B+. This negative pulse causes transistor Q4 to conduct in a path including diode D2, transistor Q4, resistors R15, R16 and resistor R8 to ground. This flow drives the base of transistor Q5 positive rendering the NPN transistor conductive from B+ through resistors R14 and R17 to transistor Q5 and thence through transistor Q1 and resistors R7 :and R8 to ground. This flow maintains the necessary negative bias on PNP transistor Q4 to keep it conducting so that in this way flip-flop 17 achieves a stable state. In this stable state, a positive potential applied through diode D6 back biases diode D1 and places a continuous positive potential on transistor Q2 sufficient to make it continuously conductive. As a consequence, the lamp `14 is lit steadily through the same circuit through which is previously flashed.

When the monitored point returns to normal, the sensing means 12A or 12B also returns to its normal condition, thereby causing a positive potential to be reimposed on the base of transistor Q1 cutting it off and i cutting off conduction yto ythe gate 13 so that the lamps 14 are extinguished. At the same time, the conduction path from transistor Q5 is interrupted so that the interruption of current fiow through transistor Q5 causes transistor Q4 to cut off thus placing the fiip-liop back in its nonconducting state.

In order to test the circuit, test push button 20 is closed through resistor R1A similar to the resistor R1 and providing a similar circuit through diode D7 to that provided by the flow condition of the sensing means 12A or 12B so that a flashing condition is produced. Holding the test push button closed and pressing the acknowledge push button will close switch 19 permitting test of the flip-flop 17 and acknowledge circuitry.

It will be clear to those skilled in the art that some simplifica-tion in the circuit module is possible if the sensing means is always to be la normally open contact or always to be a normally closed contact. With a normally open contact, for example, the gate 11 can' be eliminated and its function combined with gate 13 such that the contacts of the sensing means are in series with the collector and emitter of transistor Q3, for example, and these contacts provide the only current flow path to ground through the transistor. The circuit illustrated in FIG. 3 is preferred for general use, however, because of a versatility enabling change from normally open to normally closed contacts, or vice versa, as required in the field.

Referring next to FIG. 4, the lblock diagram shown has essentially the same elements as those of FIG. 1, and corresponding elements are designated by the same number designators. There is added, however, the flip-flop' 22 which has an effect on flip-fiop 17, and in turn, is affected by flip-flop 17. Flip-flop 22 is so located -before gate 13 that as an alert condition is sensed by contacts 12A or 12B (whichever is employed) the signal will be first applied to the flip-flop 22 causing it to change state to a stable state which will be maintained even if the alert condition passes and the contacts return to normal. In such event, the flip-flop 22 causes the signal to be m-aintained on gate 13 and the light continues to burn until actuation of acknowledgement switch 19 which causes iiip-fiop 17 to change state as in the circuit of FIG. 1. This change, in turn, has the effect of placing flip-flop 22 into a condition whereby it maintains gate 13 only so long as a .signal is imposed 'by the -alert condition of the remote contacts. After acknowledgement, the contacts of the sensing means return t-o normal, the light of the lamps 14 will go out. This sequence is indicated on the, sequence chart of FIG. 5. Details of a preferred embodiment of the circuit are shown in FIG. 6.

Referring to the circuit diagram of FIG. 6, the input gate 11 yhas been combined with the first flip-flop 22, transistor Q1', serving with transistor Q6 in this fiipflop circuit. Transistor Q6 is connected in circuit from the B+ lpower supply through resistors R3', R20, R19, transistor Q6 and resistors R7 and R8 to ground. Whereas minor circuit changes necessitate the change in resistor values, and in some cases changes in the type of transistor employed, in other respects the circuit except for the ip-op 22 and its related circuitry are essentially the same. Here and elsewhere the same designator primed indicates the same kind of element in the same general function but of s-ome different type or value. Thus, when an alert signal is imposed on the base of transistor Q1' causing it to conduct from B+ through diode D2, through transistor Q1', resistors R21, R22, and R8 to ground, a fiip-fiop action similar to that of flip-flop 17 is initiated for flip-flop 22. The conduction raises `the potential on the base of the NPN transistor Q6 causing it to conduct through resistors R3', R20 and R19, transistor Q6, and resistors R7 and R8 to ground. This current flow, in turn, lowers the potential on the base of PNP transistor Q1' maintaining its conduction.

When transistor Q6 is rendered conductive gate 13 and its transistor Q2' is able to transmit current through resistor R5', R6', transistor Q2, transistor Q6 and thence through resistors R7 and R8 to ground. Transistor Q3' again serves as an amplifier of signals applied to its base and when transistor Q2' is conductive it permits current flow which causes the lamp 14 to light. Since the flasher 16 applies an alternating positive and negative signal to the base transistor Q2' to turn it on and off, it produces flashing of the lamp 14 through control of Atransistor Q3'.

The negative pulse that trips flip-flop 22 actuates the audible module 18 in the same way that the audible is actuated in FIG. 3.

When the acknowledge push button is pushed closing switch 19, hip-flop 17 is rendered conductive exactly in the manner described in connection with the simil-ar flipflop in FIG. 3, the diode D1 is back biased by a constant positive signal through diode D6 which causes transistor Q2' to conduct and thereby causes the lamp 14 to burn steadily exactly as it did in connection with the arr-angement of FIG. 3.

The ip-fiop 17 applies a positive potential to flip-flop 22 through diode D7 through transistor Q4 to the base of PNP transistor Q1'. When 12A returns to normal flipflop 22 will go out.

In tes-ting, the test push button closes switch 20 causing Q1 to act exactly as it does in response to sensing means contacts 12A or 12B, whichever is used.

As will be readily appreciated by those skilled in the art, the basic circuit shown in FIG. 1 itself can be varied considerably in its effect and sequence of opera-tion by relatively few changes. One example of such a modification Iis described in FIG. 4. Practical circuitry for each annunciator point circuit as shown in block diagrams can also vary greatly. FIGS. 3 and 6 have shown and described as preferred embodiments of practical Icircuitry of their respective cases and it will be apparent to those skilled in the art that many other variations are possible. Two other modifications to give different effects and sequences are shown in FIGS. 7 and 9 and a sequence chart showing the sequence of the operation of each of them is provided in FIGS. 8 and l0, respectively.

Referring to FIG. 7, it will be seen that the system of FIG. 4 has been modified so that flip-flop 17 in response to the actuation of acknowledgment button no longer returns flip-flop 22 -to its initial state. Thus, in this embodiment of the present invention, not only does the flip-flop 22 hold the signal on the signal terminals of gate 13 when the sensing means returns to normal before acknowledgment but also when the sensing means returns to normal after acknowledgment, as can be seen in the sequence table of FIG. 8. In this annunciator point the returning to normal of the contacts 12A or 12B (whichever -one is employed) even after acknowledgment, does not turn off the lamp 14. The acknowledgment through flip-flop 17 back biases the flasher 16 and thus causes the lamps to burn steadily and it also preferably turns off the audible 18 through a separate pole on switch 19. However, after the system returns to normal, it is necessary to reset the annunciator to normal condition by press- `ing the reset switch push button which returns fiip-fiops 17 and 22 to normal condition and allows the rest of the system to return to normal condition. The circuitryis not shown, but to accomplish this purpose, the circuitry of FIG. 6 is modified by omission of diode D7. The reset switch may be used to extinguish the flip-flops by applying the proper potential to cut off one of the pair of transistors in each case, as for example connecting the bases of transistors Q5 and Q6 to ground through a normally open reset switch.

Referring to FIG. 9, a still further modification is illustrated. The reset feature of FIG. 7 is present and the system operates generally as FIG. 7 does. This system, however, :is so arranged that, upon return to normal, flipflop 17 will `be reset in its original state thus removing the back bias from flasher 16 and permitting the flashing signal to be imposed on gate 13 through amplifier 15 to the lamps 14 causing them to flash. This i-s made possible by a conduction path feeding to flip-flop 17 through amplier 25 of any signal which indicates a change in state. Thus, the opening of normally closed sensing means contacts 12B, if they are employed, or alternatively the closing of the normally open sensing means contacts 12A, whichever system is used, will produce a pulse through amplifier 25 to set the flip-flop 17 .in its initial state. Rectifier means can limit the pulsing to the particular direction of the pulse involved when the return to normal from alert occurs and thereby prevent its action when the initial alert occurs. This makes it possible to use a separate audible module 24 in addition to audible 18 which in other respects, however, may be identical to audible module 18 but preferably makes a different sound. This audible module 24 is preferably triggered by a pulse `and may be D.C. decoupled by amplifier 25 which, as previously noted, passes pulses. I ust as audible 18 is provided with a separate set of contacts associated with the acknowledgment switch 19 to turn off that audible, so audible 24 may be provided with a pair of contacts interrupting its signal when actuating the reset means 23. The reset contacts at the same time set the annunciator point back to normal just as they do in the case of the annunciator point of FIG. 7. It will also be noted from the sequence of FIG. l that the audible 24 will sound at any time the sensing means returns to normal. Thus, even though the return to normal occurs during the flashing period of the lamps, the fact that i-t does return to normal may be ascertained by the energization of the second audible which as above noted is preferably of a different tone from the first audible.

It is possible to devise much more complex systems using the same basic circuitry. For example, it is possible to use lock-out techniques to obtain the alternative energization of lights of different colors, such as red and white lights, one to indica-te the first in a series of alerts and the other to indicate subsequent alert signals. In the description which follows, the first alert will be represented by a red light whereas the second alert will be represented by a white light. Of course, any different colored lights or merely differences in locations `or other differences than in color may be employed to distinguish the first from later alerts.

As can be seen in FIG. 11, the red light and the white light 14R and 14W, respectively, each have their own gate 13R and 13W and amplifier ISR and 15W, respectively. As in the other cases, either normally open or normally closed contacts can be employed as a sensing means using contacts 12A or contacts 12B. The gate feature, as in the FIGS. 4-6 embodimen-t and those following, is combined with flip-flop 22 which functions to hold the red light on in the event the sensing means returns to normal. Gate 22 also functions to actuate Iaudible circuit 18. The test circuit employing test switch is essentially the same as the circuits for sensing means except that gate 25 is employed in this line to flip-flop 22. The acknowledgment circuit is essentially the same as that used in other embodiments and employs a flip-flop actuated by pressing button closing acknowledgment contacts 19. The acknowledgment push button as indicated in connection with previous systems may be provided with a second set of contacts which interrupt the audible circuit 18. The reset switch 23 functions slightly differently as will be explained. The flasher 16 operates essentially as described in previous embodiment but is used for both lights. Gate 13 is the back biased diode arrangement described in the other embodiment. In addition, it is necessary to employ the necessary lock-out and sequencing circuitry which constitutes most of the balance of the system. Again, the whole circuit can be 8 printed on a single card, represented by the circuitry within the dashed lines`10.

The circuit of FIG. ll operates as follows. Upon the occurrence of an alarm at the output of contacts 12A or 12B, the flip-flop 22 has its state changed thereby energizing the audible circuit 18. This also places a signal in the complex and or but not gate 13W which will be described later and a signal on the lock-out gate 26. If the signal is the first within its lock-out group, gate 26 will permit the signal lto pass to flip-flop 27, thereby changing its state and impressing a signal on gate 13R. The output of flip-flop 27 through gate 26 feeds back a positive signal locking out gate 13W so that no signal can be applied to amplifier 15W. Before acknowledgment, the flasher 16 imposes a signal through gate 13 on gate 13R to cause the red lamp 14R to ash. However, following acknowledgment by closing contacts 19, the flip-flop 17 through gate 4t) is set to provide back biasing on gate 13 which effectively cuts off the flasher and imposes a steady signal on gate 13R, thereby allowing the red light 14R to bi1-rn steadily. Pressing the reset butt-on 23 will reset the flip-flop 27 through gate 42 and extinguish the red light. This, in turn, removes the positive lock-out on gate 13W, thus allowing it to conduct and igniting lamp 14W. Pressing the acknowledgment buttons closes switch 19 and also closes an additional set of contacts to extinguish the audible in the way previously described.

In the event that the signal applied at this point is subsequent to a signal applied at another point, the lock-out bus will impose a signal on gate 26, causing that gate to reject the signal impressed upon it. In that event, flipilop 27 will remain in its initial state and will not impose a signal on gate 13W. Gate 13W having a signal from flip-flop 22 provides an output through gate 13W to white lamp 14W. By virtue of the flasher 16 being connected through gate 13 to gate 13W, the white light will flash alternately on and off. The closing of lthe acknowledgment contacts, however, will change the state of flip-op 17 causing it to back bias gate 13 to prevent the flasher signal from reaching the gate 13W and, therefore, the lamp will burn steadily. When gate 13W and flip-flop 22 are cut ofi, the signal passing back through gate 28 will reset the flip-flop 17 so that on the next cycle flashing 'can occur.

The sequence thus described is illustrated in the sequence chart of FIG. 12. It will be observed in this chart that while the red signal continues to bu-rn after the sensing means contacts return to normal, the white lamp signal is extinguished.

Referring now to the circuit diagram of a preferred embodiment of the FIG. 11 `annunciator point shown in FIG. 13, the similarities lto the previously illustrated and described circuitry of FIGS. 3 and 6 will be apparent. Corresponding parts have been given similar designators and those parts in which many of the values of the cornponents have been changed have been given the same designator but with the addition of a prime thereto. p

Thus, it will be observed that the arrangement of normally open and normally closed terminals or contacts are the same so that if the normally cl-osed contacts are to be employed and connected to the B+, the normally open contacts are omitted and the terminal jumpered directly to ground, in which case, the full B+ voltage appears across resistor Rl. In this case, the test push buttons are connected across `a resistor R25 and through a diode D8, but in other respects acts exactly as the normally open contacts in lowering the potential on the base of transistor Q1 which, because it is a PNP transistor will cause it to Iconduct. Transistor Q1 conducts from B+ through diode D2, resistors R26 and R27 and resistor R8 to ground. Conduction of transistor Q1 raises the potential on the base of transistor Q6 thereby causing it to conduct since it is an NPN type transistor. When transistor Q6 is rendered conductive, transistor Q8 which is biased to be normally conductive permits a flow of current from the B+ through resistors R3 and R20' to tranpositive pulse renders transistor Q10 conductive from B+ through resistors R28 and R29, transistor Q10 and resistors R7 and R8 t-o ground. This conduction, in turn, lowers the potential onthe base of transistor Q11 rendering it conductive from B+, through diode D2, the

`transistor Q11, resistors R30 and R31 and resistor R8 to ground. The flow through transistor Q11 maintains the posi-tive potential on the base of Q10 to keep it conductive.` Rendering flip-hop 27 conductive provides a conductive pathv from B+ power supply through resistors RSR, R6R, transistor Q2R, transistor Q10 and resistors R7 and R8' to ground. At this point, the flasher 16 is elective to alternately turn transistor Q2R on and olf by applying alternating positive and negative pulses to its base. This provides lamp 14R with a ilashing signal in the rnanner described above with respect to other circuits where transistor Q3R which provides amplilier 15R which actually controls current to the red lamp 14R.

' Also under these circumstances, unless a signal occurs `within few milliseconds after the first signal recorded at this point, the lock-out circuit will be etective. This circuit is eiective due to the conduction of transistor Q11 whichimposes a positive potential at the lock-out gate `29. This path is from B+ -through diode D2, transistor Q11, and`diode D10 to the lock-out bus or lock-out gate 29. This signal on the lock-out bus which is common to all points in the group back biases diode D9 and prevents 'the-positive pulse across capacitor C3 from triggering -ipilop 27 at other points and thus prevents other red 'lights from coming on. Another conductive path through -diode D11 per-mits the positive potential present when 1 transistor Q11 becomes conductive to be applied to the base of PNP transistor Q9 in order to cut olf -that transistor and current -ow through it. Cutting off transistor Q9 cuts off transistor Q8 and hence transistor Q6 but by this time flip-flop 27 has been set and the red light is on and will stay on hashing or steady (acknowledged) until the reset button closes switch 23 to turn it off.

Acknowledgment off :a flashing red light in the audible rsignal .is accomplished lthrough closing the acknowledgment swito'h 19. This preferably also provides a separate switch pole to interrupt the audible.

i momentarily pulls down the potential of the :base of the PNP transistor Q4thereby causing it to conduct. Its conduction from the B+ is through diode D2, transistor Q4 and resistors R15, R30, R32 and R8 to ground. This conduction raises the potential on the ibase of transistor I,Q5 and therelby renders it conductive from the B+ through resistors R14, R17', transistor Q5, diode D12, transistor vQ and resistors R7 and R8 to ground. This conduction, in turn, sustains the conduction of t-ransistor Q4 and in this way a steady positive potential is applied through diode D6 to back bias the asher diode D1 and apply a stead-y potential at the base of transistor Q2R to cause the red lamp 14R to burn steadily.

When it is desired to reset the annunciator poin-t, the push button ope-rating reset switch 23 is actuated to close that switch and this connects ground to the 'base of transistor Q10 through resistor R33, then diode D13 thereby cutting off the transistor Q10 which, in turn, cuts oli transistor Q11 thusl extinguishing the flip-flop 27. The Aturning off of transistor Q10 cuts off the signal current VVthrough gate transistor'-Q2'Rvand, therefore, deprives Closing switch 19 l0 amplifier transistor Q3R and lamp 14R of the necessary current to light said lampand the lamp is extinguished. With Q11 cut oiT, the positive potential is removed from the base of Q9 through D11 allowing gate 13W to conduct. With flip-flop 17 conducting, a positive potential is applied to the Ibase of Q2W through diode D6 and R4. Tihus, the white light 14W will burn steadily. It will |be Idiscussed later how the lwhite light 14W will automatically reset on return to nonmal condition. With Q11 in a nonoonducting state, the positive potential is removed from the lock-out .gate thus permitting the next alert that occurs to flash Ithe red light 14R to indicate a new rst alert in a series. Note this can occur even though a white light is ligh-ted in another module.

Let us assume now that 4the signal at this poin-t is su'bsequent to the irst signal so that a positive potential has |been applied to the lock-out bus. When the potential is applied to the :base of transistor Q1 causing it to conduct from the B+ through diode D2, transistor Q1, and resistors R216, R27 and R8 to ground, transistor Q6 will be rendered conductiveas Ibefore, transistor Q7 will Ibe rendered conductive as |beore, -throu-gh transistor Q8, transistors Q7, Q9 and resisto-rs R7 and R8 t-o ground. The audible 18 will be sounded Iby the pulse across capacitor C1 as before. However, the pulse attempting to pass through diode D9 will encounter a positive back biasing from the lock-out gate and the point first alerted which prevents it from reaching capacitor C3. Hence, flipflop 27 will not turn on. Since no cut-olf positive poten-tial is applied through transistor Q11 to .the base of transistor Q9 via diode D11, conduction is maintained through transistor Q9. Since transistor Q9 remains conductive current can flow from B+ through resistors RSW, R6W, .through the and or ibut not gate 13W consisting of transistors Q2W, Q7 and Q9 and through resistors R7 and R8' to ground, A ow of current through transistor QZW causes amplifier Q3W to turn on white light 14W. However, the 'base of transistor Q2W is connected to the llasher 16, inthe same manner Q2R is, and until acknowlflop 27 causes it to 'be hel-d on. However, with the white light no such ilip--op is interposed. As long as the White light is llashin even return to normal of the sensing contacts will not extinguish it 'because flip-flop 22 will remain on. However, the positive potential produced |by transistor Q4 following acknowledgment acting through vdiode D15 causes PNPtransistor Q8 to cut off which l turns olf transistor Q6 by depriving it of a conduction path. Transistor Q1 will remain on as its path is through contact 12A or 12B. With 12A or 12B returning to normal, Q1 'will fbe cut off as its conducting path will be broken. This in turn deprives the Ibase of transistor Q7 of its required positive potential and hence interrupts the `path through transistor AQ2W so that sensing contacts 12A Ior 12B return to normal. With gate 13W non-conducting, the emitter of Q5 has its path broken through diode D25, Q7, Q9, R7, R8. Flip-Hop 17 will stop conducting.

From 4what has been said albove, it will ibe appreciated that many variations can Ibe achieved in the circuit of FIG. 13 to accomplish other sequences and, in view ofthe teaching of the present invention, such modifications will occur to those skilled in the art. In the circuitry shown by way of illustration flip-flop circuits using one PNP and one NPN transistor have been used since this makes it possible to turn the flip-flop completely off or completely on. It will lbe apparent to .those skilled in the art that flip-flop circuits shown have been designed to be turned off normally in order t-o save power, another flip-flop .may be substituted as desired in other installations. It will be apparent, however, that the circuits used are designed particularly for transistors With which they may be inexpensively constructed. Other elements substituted for transistors in suc'h circuits would be quite expensive and/ or Kwould defeat the purpose of compactness.

In FIGS. 3, 6 and 13 component sizes -or types have been indicated directly on the drawing. These sizes and types in each case are intended to lbe by way of example and not limitation as it will be clear to .those skilled in the art many modifications might be made. The circuits illustrated accommodate a B+ range of at least 15-150 volts D.C. and 100-130 volts A.C., for example.

FIG. 14 is supplied merely to show the relationship of one point with respect to other points in a given group. Within a given group, there may be many points up to a certain reasonable limit of say 200 points. All points in a group share such things as the B+ power supply and preferably a common ground. They may share the same audible 18 and the same flasher 16 and may even share such push button contacts as those for test 20, Iacknowledgement 19 and reset 23. In the case of the reset push button, only such points as require reset would be connec-ted. In the case of a first in, first out sequence employing a lock-out circuit, such as those of FIGS. 11-13 the lock-out circuit to function as such must be common to the whole group. The only external circuitry necessarily exclusive to each point are the sensing means or contacts which may -be normally open and normally closed as previously described and one or :more sets of lights associated with and identifying that point. Where white lights are used, for example, in the first in, first out sequence of FIGS. ll-l3, observation of the lights of all the points in a `group will tell immediately which points are under alert conditions and which was the first to assume that condition.

Since the individual points may be made on small cards, as printed circuits using transistor and other components of miniature size, a very small structure can be constructed and the total circuitry of the annuncia-tor system may be kept extremely compact. It is .also possible to make the power supply B+ and external circuitry, such as the audible circuit or circuits andthe flasher in printed circuit card form. Not only is .this highly convenient but it allows ready replacement of a faulty point by simply substituting one card for another in a plug-in type of arrangement to which these cards 'in the circuitry described are readily adaptable. It will be seen, therefore, that specific circuits designed expressly for use with small, compact, rugged, solid state devices enable not only major savings in cost, but yalso major savings in space, yet at the same time they may be relatively temperature insensitive in any normal environment where they might be used.

Modifications of the annunciator point circuit of the present invention both broadly and specifically -has been .shown and described .and other modifications suggested. Still other variations and modifications within the scope (of the claims will occur to those skilled in the art. All :su-ch variations and modifications are intended to be within the scope and spirit of the present invention.

I claim:

1. An annunciator point for monitoring the condition of a device which has normal and alert conditions comprising a lamp which has a normal condition indicating the device is in normal condition, sensing means for sensin-g |alert and normal conditions producing a signal only in alert condition, a first gate means havinginput, output and cont-rol terminals with its output terminal coupled to the lamp and its input terminal coupled to the sensing means to derive a continuous input signal from the sensing means in the alert condition, and a flasher tcpnneted tp the control terminal and providing a control signal at the first gate means in order to flash the lamp alternately on and off and acknowledgment means connected to said control terminal and including a flip flop distinct and separate from the first gate means, said flip flop having an input terminal -connected to a manu-ally controlled acknowledgement switch, an output terminal coupled to the control terminal of the first gate means through which terminal said acknowledgement means is able' to overcome the effect of the flasher when the flip flop is in the state selected -by the acknowledgement switch, a further terminal coupled to the first g-ate means other than to the 'control terminal so that upon discontinuance of the signal current flow through the gate means the flip flop will be restored to the state in which it cannot overcome the effect of the flasher, and second gate means connecting the input terminal of the first gate means and the sensing means, thereby to provide isolation of the flip flop from the sensing means.

2. An annunciator point for monitoring the condition of a device which has normal and alert conditions comprising a lamp which is out when the device `is in normal condition, sensing means for sensing alert and normal conditions and lighting the lamp `only in alert conditions, a first gate 4means having input, output and control terminals with its output terminal coupled to said lamp and its input terminal coupled to the sensing means to derive a continuous input signal from the sensing means in the alert condition, a asher connected to the control terminal and providing a control signal at the first gate means in order totlash the lamp alternately on and off and acknowledgmentv means connected to said control terminal and including a flip flop distinct andv separate from the lfirst gate means, said flip flop having an input terminal connected to a manually controlled acknowledgment switch, an output terminal coupled to the'control terminal of the first gate means through which terminal said acknowledgment means is yable to overcome the effect of the flasher when the flip flop is in the state selected by the acknowledgement switch, a further terminal coupled to the first gate means other than to the control terminal so that upon discontinuance of the signal Acurrent flow through the gate means the flip flop will be restored to the state in which it cannot overcome the effect of the flasher, and second gate means connecting the input terminal of the first gate means and the sensing means, thereby to provide isolation of the flip flop from the sensing means.

3. The annunciator point of claim 2 in which the asher is connected to'the control terminal of the first gate means through a diode and the flip-flop produces a signal to back bias that diode and maintain a steady signal on th gate so that flashing is terminated.

4. An annunciator point for monitoring the condition of a device which has normal 'and` alert conditions and for use with'a group of similar annunciator points to determine whether it was first to signalan alert condition or -subsequent to some other point comprising first and`second lamps each of which has a normal condition .indieating the device is in normal condition and producing .a signal only in alert condition, sensing means for sensing alert and normal conditions, first and second gate means having at least input, output and control terminals, the output of the firstgate being'coupledA to the first lamp and 4the output of the secondy gate being'coupled to the second lamp andthe input of each gate being direct current coupled to the Asensing means to derive a continuous signal from the sensin-g means in the alert condition, lock out gate means in said coupling to said first gate input for blocking the signalA from the sensing means to the input of the second gate and impressing the signal on the first gate and generating blockin-g'signal to prevent the first light of other similar poin-ts in the group from assuming its alert condition if no blocking signal from another point is applied to said'lock out gate, and

which blocks the signal to the first gate and permits the signal -to reach the second gate if a blocking signal from another point is applied to said lock out gate, and flasher means connected to the control terminal of each of the first and lsecond gates and providing an intermittent signal at said gates to flash ltheir respective lamps alternately on and off.

5. The annunciator point of claim 4 in which acknowledgment means including a flip-iiop and a manually controlled switch to set said flip-flop into a predetermined state, is employed and coupled with the flasher to the control terminal of each of the -first and second gates in order to overcome the effect of the flasher and cause the lamp whose control gate has a signal to assume a steady condition indicative of continuing alert.

6. A circuit module for van annunciator point for monitoring the condition of a device which has normal and alert conditions comprising a series resistance voltage divider providing a mid-terminal and first and second end terminals at its respective ends, the first end terminal being connectable to one electrical potential, a further series resistance connected at one end to the second terminal of the voltage divider and providing a third terminal at its other end, a first gate means having input, output and control terminals with the output terminal being connecta-ble to a lamp, the input terminal being direct current coupled to the mid-terminal of the voltage divider to derive a continuous input signal in the alert condition, and the control terminal being connectable to a flasher in order to flash the lamp on and ofi, acknowledgement means connected to said control terminal and including a fiip-flop distinct and separate from the first gate means, said flipflop having an input terminal connected to a manually controlled acknowledgement switch, an output terminal coupled to the control terminal of the first gate means through which terminal s-aid acknowledgment means is able to overcome the effect of the flasher when the flip-flop is in the state selected by the acknowledgement switch, .and a further terminal direct coupled to the first gate means other than to the control terminal so that upon discontinuance of the `signal current flow through the gate means the flip-flop will be restored to the state in which it cannot overcome the effect of the flasher, and second gate means connecting the input terminal of the first gate means and the sensing means thereby to provide isolation of the flipflop from the sensing means, the continuous input signal from the sensing means being derivable either from the closing of normally open contacts oonnectable between the third terminal and a second potential or from the opening of normally closed contacts connectable between the second terminal `and the same potential .applied to the first terminal provided that the third terminal is connected to a second potential.

7. The circuit module of claim 6 in which a terminal for a test switch is connected to some point along the series circuit including the voltage divider and the further series resistance whereby the test switch may be -used to apply a continuous input signal to the input terminal of the gate means.

8. The annunciator point of claim 1 in which a series resistance voltage divider having end termin-als and at least one middle terminal is connected at its middle terminal to the input terminal of the gate means and connected at one end terminal to one potential, the sensing means being =a normally open contact connected between the other end terminal and a second potential, whereby upon closing the normally open contact a constant signal is applied to the input terminal of the gate means.

9. The annunciator point of claim 1 in which a series resistance voltage divider having first and second end terminals and at least one middle terminal is connected at its middle terminal to the input terminal of the gate means and connected at its first terminal to one potential, a f-urther resistance connected -at one end to the second terminal of the voltage divider and provided at its other end with a third terminal which is connected to a second potential, the sensing means being a normally cl-osed contact connected between said second contact and the same potential to which the first terminal is connected, whereby upon opening the normally closed contact a constant signal is applied to the input terminal of the gate means.

10. An `annunciator point for monitoring the condition of a device which has a normal condition indicating the device is in normal condition, sensing means for sensing alert and normal conditions and producing a signal upon alert condition, a first fiip-llop direct current coupled to the sensing means to derive a continuous input signal from the sensing means in the alert condition but set in a stable st-ate by momentary alert indication from the sensing means to retain the signal imposed on said input terminal even after the sensing means returns to normal, a gate means having output and control terminals with the output terminal coupled to the lamp and its input provided by the first flip-flop, a flasher connected to the control terminal and providing a control signal at the gate in order to flash the lamp alternately on and off and acknowledgment means connected to said control terminal and including a second flip-flop `and a manually controlled switch, said acknowledgement means overcoming the effect of the flasher when the flip-flop is in the state selected by said switch.

11. The annunciator of claim 10 in which the first flip-flop conducts until the second flip-flop is reset at which time said flip-flop causes said first flip-flop to return to its other state provided, however, that conduction may continue through a portion of the first flip-flop to maintain an alert signal on the gate as l-ong as the sensing means indicates an alert condition.

12. The annunciator of claim 10 in which 4a reset switch is provided to reset said second flip-flop by application of required reset potential and in which the first flip-flop conducts'until the second flip-flop is reset by said reset switch from its acknowledged state to its other state removing the signal from the control terminal of the gate if no signal remains from the sensing means but retaining the signal if a signal continues from the sensing means.

13. The annunciator point of claim 10 in which the second flip-flop is arranged to be reset to its original state Iby the acknowledgement means.

References Cited by the Examiner UNITED STATES PATENTS Re. 24,031 671955 Marmorstone S40-213.2 2,832,948 4/1958 Derr et al. 340-2131 2,858,528 10/1958 Diener 340-213.1 3,029,421 4/ 1962 Beguin S40-213.1 3,039,085 6/1962 Keller 340-2132 3,099,824 7/1963 Vitt et al. 340-2132 3,128,456 4/ 1964 Silliman et al S40-213.1 3,155,950 1l/l964 Foster 340-213.2 3,193,814 7/1965 Foster 340-223 3,218,621 11/1965 Foster 340-2132 FOREIGN PATENTS 1,205,177 8/ 1959 France.

NEIL C. READ, Primary Examiner.

THOMAS B. HABECKER, Examiner.

R. M. ANGUS, D. YUSKO, Assistant Examiners. 

1. AN ANNUNCIATOR POINT FOR MONITORING THE CONDITION OF A DEVICE WHICH HAS NORMAL AND ALERT CONDITIONS COMPRISING A LAMP WHICH HAS A NORMAL CONDITION INDICATING THE DEVICE IS IN NORMAL CONDITION, SENSING MEANS FOR SENSING ALERT AND NORMAL CONDITIONS PRODUCING A SIGNAL ONLY IN ALERT CONDITION, A FIRST GATE MEANS HAVING INPUT, OUTPUT AND CONTROL TERMINALS WITH ITS OUTPUT TERMINAL COUPLED TO THE LAMP AND ITS INPUT TERMINAL COUPLED TO THE SENSING MEANS TO DERIVE A CONTINUOUS INPUT SIGNAL FROM THE SENSING MEANS IN THE ALERT CONDITION, AND A FLASHER CONNECTED TO THE CONTROL TERMINAL AND PROVIDING A CONTROL SIGNAL AT THE FIRST GATE MEANS IN ORDER TO FLASH THE LAMP ALTERNATELY ON AND OFF AND ACKNOWLEDGMENT MEANS CONNECTED TO SAID CONTROL TERMINAL AND INCLUDING A FLIP FLOP DISTINCT AND SEPARATE FROM THE FIRST GATE MEANS, SAID FLIP FLOP HAVING AN INPUT TERMINAL CONNECTED TO A MANUALLY CONTROLLED ACKNOWLEDGEMENT SWITCH, AN OUTPUT TERMINAL COUPLED TO THE CONTROL TERMINAL OF THE FIRST GATE MEANS THROUGH WHICH TERMINAL SAID ACKNOWLEDGEMENT MEANS IS ABLE TO OVERCOME THE EFFECT OF THE 